Embodiments of the present application relate generally to methods and apparatus for electronic and electrically activated displays. More particularly, although not exclusively, these embodiments are concerned with small, low cost, low power electronic and electrically activated displays for use in product and packaging labels.
It is generally desirable in the art of making smart labels and smart packaging products to be able to relate information obtained by the smart label sensor in a low energy and low cost manner. Such methods of relating information can be used in quality control and quality assurance activities to improve product quality, safety, and security. Information may be related in either a machine-readable, human-readable, or a combination of both human and machine-readable forms.
To accomplish such information transfer, it is known in the art that certain industry standard embedded radio frequency (RF) transmitters or static bar codes may be used to relate machine-readable information. Static printed labels and enzymatic tags may be used to relate human-readable information. Liquid crystal displays (LCD) or light emitting diode (LED) displays may be used to relate both machine and human-readable information.
When considering the update in information made available by the smart label or smart package, a static bar code or static printed message is not useful. When considering the limited energy available to a smart label or package, industry standard RF transmitters, LCD, and LED displays are not practical for extended use. Passive RF transmitters may be used in limited application without additional energy requirements, however, better reliability is obtained with active, or battery assisted, RF transmitters. Industry standard LCD options are further constrained by their useful operating temperature range. Enzymatic and similar displays presently provide only a general indication of an event without variations or details.
Additionally, when considering the cost of goods required to build such displays into smart labels and smart packages, even at the smallest levels of integration (deep sub-micron), using fully custom Application Specific ICs (ASICs), the cost of goods may be too high to be applicable in a typical case-ready packaging situation. Cost sensitivities drive the need for lower-cost and lower-power methods for relating information for smart label and smart packaging devices.